The invention relates to a small zoom lens system having a high zoom ratio and an image pickup apparatus including the same.
Zoom lenses used in still cameras or video cameras require excellent optical performances, high zoom ratios and small sizes. Furthermore, as electronic devices such as personal digital assistants (PDAs) and mobile devices currently become popular, digital cameras or digital video units are included in most of the electronic devices and thus demand for small cameras is increasing.
Unlike film cameras that are carried by users only when needed, many users carry digital cameras ordinarily and thus small, thin and light digital cameras are in high demand. A small and thin digital camera may be realized by adopting a retractable barrel for extending a lens out of a camera in a photographing mode and accommodating the lens within the camera when the lens is not used, or an inner zoom barrel for reducing the thickness of a lens system by using a reflector such as a prism. In an optical system including a prism, the thickness of the optical system may be reduced by refracting an optical path by 90° in the middle of the optical system by using the prism.
When a small digital camera is realized by adopting an inner zoom barrel for reducing the thickness of a lens system by using a reflector such as a prism or a mirror, various methods such as a method of reducing an overall length of a lens system or a method of suppressing the sensitivity of each optical component are suggested.